Circuit interrupter



March 22, 1938. H, LINGAL ET 2,112,033

CIRCUIT INTERRUPTER Filed Sept. 12, 19 54 s Sheets-Sheet 1 a/ a 7 3 79 E a/ 4 65 75 E WITNESSES INVENTORS Z Harry J Linga! and Rofierz dfll'c'kz'nson.

- ATT RNEY March 22, 1938. H. J. LINGAL ET AL CIRCUIT INTERRUPTER 5 Sheets-Sheet 3 Filed Sept. 12, 1934 INVENTORS Harry J Linga/ and Rob d flickmsozz.

A ORNEY WITNESSES Patented Mar. 22,1938

UNITED STATES PATENT OFFICE CIRCUIT INTERRUPTER- Application September 12, 1934, Serial No. 743,697

6 Claims.

Our invention relates to circuit interrupters and has particular application to high capacity circuit breakers for use with power distribution systems.

The design of circuit breakers for this type of service presents a rather complex problem to the electrical art. More and more separate power systems are being interconnected into large networks, with the result that the amount of power which is available at any one point in these systems is becoming increasingly large. Despite this, fault conditions in these interconnected systems must be'cleared very rapidly or the stability of the entire system will be impaired, and to further complicate the problem there is an increasing tendency on the part of public utility companics to utilize the maximum possible voltage on the interconnected systems, in order to minimize transmission losses. Thus, a commercially successful device for this type of service must be capable of interrupting very large amounts of power, at high voltages, within a very short period of time, and the principal object of the present invention is the provision of a circuit breaker which shall meet these requirements more satisfactorily than the previously known devices.

In the existing state of the art, the basic problem of circuit interruption resides in the extinction of the are which is formed incident to the separation of the current carrying contacts. This problem has been investigated. at great length in recent years, and it is fairly well established that are extinction may be most efiiciently accomplished by turbulently intermingling a quantity of fluid either in the gaseous or liquid state with the arc path proper. The greater the turbulency and the greater the quantity of unionized fluid which is passed through the arc stream, the more eflicient the arc extinguishing operation becomes. There are two general methods for accomplishing this intermixing. One is the introduction of a jet of fluid into the arc stream, and the other is the moving of the arc in such manner that a turbulent intermixing' results from the movement, or in such manher that a jet is produced as a result of such a movement.

Our invention is concerned particularly with devices wherein the arc is laterally moved within an arc passage normally containing a gas evolving substance. Devices of this general type have been utilized before, but the amount of movement of the arc has been definitely limited by the.

physical dimensions of the arc passage, and once the arc had been moved from one side of the passage to the other, additional movement became impossible.

This limitation created no serious difliculties for most circuits, but as the requirements of the power companies became more stringent, it has been found desirable that means should be provided for moving the are more rapidly and for a greater distance within the arc passage than had been done heretofore, this additional movement at increased speed being necessary to give increased turbulence adjacent the arc stream during the circuit interrupting operation, thereby assuring the extinction of the arc regardless of the magnitude of the overload which might be present on the system.

In our investigations along this line, we have found that if the surrounding fluid is allowed to move ahead of the moving are (such as through a vent at the end of a straight passageway) and if the arc speed is sufliciently great, a much more efficient extinguishment of the arc with a very considerable decrease in the arcing time, are energy, etc., is effected. As a further development, we have found that the most suitable arc passage is of the reentrant type, it being possible to obtain a much greater arc speed and a considerably increased fluid motion for a given field strength in a reentrant arc passage than can be obtained in a straight passage which is vented at one or both ends. This improved operation is thought to be due, at least in part, to the smaller friction losses between the fluid and the confining walls of a reentrant passage. It is to,be understood that, although fluid will move ahead of an are, under the above conditions,-the arc stream acting substantially as a piston i;here will also be relative movement between the arc stream and the fluid.

In the preferred embodiment of our invention, we provide a continuous or reentrant passage for the are which has the substantial form of a hollow cylinder. .This construction lends itself to the production of a very strong magnetic field, substantially at right angles to the walls of the reentrant passage, for moving the arc therein at a high velocity. In addition, the reentrant shape of the passage allows a greater length of arc passage for the space occupied than is possible in devices using a single passage which is not reentrant upon itself. Moreover, the reentrant construction allows the arc to be moved in recurrent path therewithin. The combined efiect of these features is to produce a device wherein the arc may be moved at greater speeds, and over greater distances, than has been possible in the previously known devices, the result of this additional movement being to produce greater turbulence and a much higher are extinguishing efliciency than the older structures. The entire structureis submerged in the arc extinguishing fluid.

The structure of our invention, therefore, provides means for defining an arc passage which is reentrant upon itself, which is lined with insulating material, and which is normally submerged within a body of fluid, and means for causing the are which is established therein during the circuit interrupting-operation to be moved laterally within the passage in order to effect its extinguishment. Since the passage is reentrant, this lateral movement may, if desired, be caused to follow recurrent paths. Arcing horns are provided at either end of the passage for facilitating the lateral movement of the arc, particularly when it is desired that the arc shall be moved in a recurrent path.

In the preferred embodiment of our invention, we utilize a reentrant passage which has the substantial form of a hollow cylinder, and provide magnetic means for causing the arc to be moved laterally therein, the path of movement comprising, substantially, a rotation about the axis of the arc passage. Also, we provide openings or pockets along the sides of the arc passage for retaining quantities of the arc extinguishing fluid therein, thus assuring adequate volume of gas for effecting extinguishment of the arc.

The exact form of the arc is not, of course, an essential feature of our invention. Any other convenient form may be used, it being necessary merely to provide means for making the passage reentrant upon itself.

We have discovered that when an arc is caused to move in a space between conflning walls, the arc stream or gas envelope surrounding the arc acts in a manner similar to a piston, and forces the fluid entrapped within the arc passage to be moved ahead of the arc stream. If the conflning walls deflne a reentrant passage and an arc is moved through this space by magnetic or other means, the fluid normally entrapped therein will be driven laterally through the arc'passage by the piston action of the arc itself. This fluid motion will tend to continue after the occurrence of a zero point in the current wave,and will tend to scavenge the arc stream and to cause a substantially homogeneous body of clean un-ionized fluid to be moved between the contact members, arcing horns, etc. The result of this movement of fresh dielectric between the normally energized parts is to greatly impede the dielectric breakdown within the arc and to assure improved interrupting performance.

In addition to the above described effect of the movement of the arc extinguishing fluid which is produced by the piston action of the arc stream. we have discovered that the moving body of liquid normally fllling the arc passage acquires considerable kinetic energy, and, during the period of current zero, it moves the ionized gas and fluid defining the arc stream proper a very appreciable distance, laterally within the are e. In one embodiment of our invention we have provided means for utilizing this movement to eii'ect a progressive lengthening of the arc thereby facilitating the arc extinguishing operation.

. In addition to the above-mentioned principal object, it is a further object of our invention to provide an arc extinguishing devi utilizing a substantially tubular are e, which shall be inexpensive to manufacture and which, at the same time, shall be very reliable in its operation.

A second further object of our invention is to provide a contact structure for circuit interrupters of the above described type which shall be so arranged that the movement of the are produced during the circuit interrupting operation shall, if desired, efiect a progressive lengthening thereof.

A still further object of our invention is to provide a circuit interrupting device which shall include separable contact means for drawing an are, means for then moving the arc laterally on suitable arcing horns to effect a progressive lengthening thereof, and means whereby the lateral movement of the arc causes fresh dielectric to be moved into the short gap normally existing between the are drawing members in order to prevent the arc from restriking across those members during the progress of the arc extinguishing operation.

These and other objects will be made apparent in the following description of two structures wherein are embodied the principal features of our invention. Both of these devices are of the liquid immersed type, but it is to be understood that manyoi' the principles of our invention are equally applicable to circuit interrupters which utilize any suitable fluid. Referring particularly to the drawings,

Figure 1 is a sectional view, partially in elevation, 'of a double break, single pole circuit interrupter utilizing arc extinguishing devices constructed according to our invention,

Fig. 2 is a sectional view, also partially in elevation, through one of the arc extinguishing devices utilized in the circuit breaker shown in Fig. 1,

Fig. 3 is a sectional view on the line HIDI of Fig. 4 is a sectional view on the line IVIV of m- Figs. 5 through 18, inclusive, are views of the various plate elements which are utilized in building up the arc extinguishing structures" shown particularly in Figs. 2, 3, and 4,

Fig. 19 is a sectional view, similar to Fig. 2, showing a modifled form of our improved are extinguishing structure which is suitable for use with the breaker shown in Fig. 1,

Fig. 20 is a sectional view on the line xx-xx of Fig. 19, and

Fig.*21 is a developed view, at a reduced scale, of the moving contact shown in Fig. 19.

The circuit breaker shown in Fig. 1 is of the conventional fluid-immersed type and includes a tank or closure l which is provided with a suitable cover 3 afllxed thereto by means such as the stud bolts 5. A pair of insulating bushings I are supported on the cover 3 through the agency of flanges and bolts 9, and each of these bushings I is adapted to support one of the stationary contact structures II and one of the arc extinguishing devices I! which together form the two breaks of the interrupter. A bridging member I! is provided for electrically connecting the two stationany contact assemblages II when the circuit breaker is in the closed-circuit position. 'This bridging member I5 is supported upon an insulatingpullrod ll andisadaptedtobeactuated by a suitable mechanism (not shown). The lower end of each of the insulating bushings I, the stationary contact structures II, and the are extinguishing device It, are normally submerged in the body of oil or other insulating fluid contained within the tank I.

anaosa Each of the contact structures H comprises a cast frame which is provided with a circular base portion 2|, a clamp portion 23 adapted to engage the lower end of the conductor 25 forming a part of the cooperating insulating bushing l, and a U-shaped portion 21 which connects the base and clamp portions. A movable contact member 29 is pivotally supported upon the base portion 29 of each of the main frame structures and is biased in the direction of the bridging member H by a spring 3|. A flexible shunt 33 serves to connect each of these movable contact members 29 with the cooperating frame structure.

The electrical circuit through the breaker is thus comparatively direct. Beginning with one of the conductors 25 disposed within the insulat-= ing bushings 5,. the current flows successively through the main supporting frame it which is afiixed to the lower end of that conductor, the flexible shunt 33 connecting the associated movable contact member 29 with the frame, the mov= able contact member itself, and thence through the adjacent upstanding portion 35 of the bridging member l5 and the central portion of the bridging member to the other stationary contact structure II, where a substantially similar path is followed.

Each of the arc extinguishing devices 03 comprisesessentially a plurality of superposed plates having aligned openings therein for defining a tubular arc passage 31 which has the substantial .iorm of a hollow cylinder. Magnetic means, which include a pair of coil members 38 adapted to be connected in series with the circuit controlled by the breaker during the circuit inter rupting operation and a plurality of iron plates, are provided for causing a radial field within the are passage 31 during the arc extinguishing oper ation. This radial field is at right angles to the are passage and, by causing the arc to be moved laterally within that are passage during the arc extinguishing operation, assures a rapid and ef= festive extinguishment thereof. Each of the devices is supported upon and held together by a central bolt or tension member 39 which is prei-= erably of insulating material.

As shown particularly in Figs. 2, 3, amid, the upper portion of each of the arc extinguishing devices l3 comprises a cap member til ofinagnetic material which is adapted to be disposed about the upper portion of the plate assemblage, thereby equalizing the distribution of the arcinoving magnetic field and for giving mechanical strength to the stack structure. This member is insulated from the plate structure proper by a. cap member 42 of molded insulating inaterial, and'both the members II and 42 are provided with a central opening 43 for permitting the passage therethrough of the main bolt 39, upon which the entire structure is assembled, and a second opening 45, which is substantially rectangular in shape, in order to permit the pas sage therethrough of the lower portion of the adjacent movablecontact 29. Immediately beneath this cap member 4| is positioned the upper of the two coils 38 which are adapted to provide the radial field within the arc passage 31 during the circuit interrupting operation. One end "of this upper coil is connected to the frame i of the stationary contact structure, and the space between the inner periphery of the coil and the bolt 39 is occupied by four sets of plates which are shown particularly in Figs. 5 through 8, inclusive. A

The upper of these sets of plates consists of an annular iron plate A! positioned immediately adjacent the central bolt 39 and an outer plate l9 of insulating material adapted to engage the inner surface of the coil 38. These plates are shown particularly in Figs. 5 and 6, and it will be seen that the outer insulating plate 49 is pro vided with a rectangular opening 5! for permitting the passage therethrough of the cooperating upstanding portion 35 of the bridging member i 5.

A single insulating plate 53 having a similar rectangular opening bi therein is positioned immediately beneath the upper pair of plates ll and at. A second pair of plates 41 and 49 are positioned beneath this upper insulating plate 53 and a second insulating plate '53 is positioned be-= neath this group. The principal function of the iron plates M is to aid in. equalizing the dis= tribution of the radial field within the arc passage proper byreducing the reluctance of the magnetic path.

One of the arcing members 55, which is shown particularly in Figs. 17 and 13, is disposed imme diately beneath the lower insulating plate 53 in each of the arc extinguishing devices. This areing member 55 is insulated from the central bolt 3% by means of an annular plate Ell of insulating .material, and it is provided with a rectangular opening at, similar to the openings ill in the plates til and 53, for permitting the passage therethrough oi the cooperating upstanding portion of the bridging member.

The next elements in the stack are those which define the arc passage proper, and they include iron plates for aiding and equalizing the radial field within that passage, plates for defining the ing plates and two groups of the plates which de= fine the outlines of the arc passage itself.

A pair of insulating plates form the first ele= inent oi each of the upper pocket defining groups.

These plates are shovvnparticularly in Figs.

and 16 and are positioned immediately beneath the upper arcing plate 55. The inner plate 59, which is of insulating material, is provided with a centrally disposed opening GB for permitting the passage therethrough of the main bolt 39 and a plurality of cutout portions 63 in the outer edge thereof for defining the fluid retaining pockets. The outer plate lit is provided with similar cooperating cut-out portions CW. Beneath these two insulating plates are positioned. one of the groups of plates shown in Figs. 13 and 14. The inner element of this set of plates comprises one of the iron plates it which is also usedin the upper portion of the stack, and an outer insulating plate (59 having substantially the same outline as the superposed insulating plate 59 (Figs. 15 and 16) is provided for insulating this plate ll from the arc passage M. A second iron plate ll forms the extreme outer portion of this set" of plates and is insulated from the arc passage by an inner liner plate 73. The next and last element in the upper pocket iorming group comprises two of the insulating plates shown in Figs. 15 and 16.

The next set of plates comprises the first of the groups of plates which define the arc passage proper, and is shown particularly in Figs. 9 and 10. it comprises one of the iron plates 41,

p which is insulated from the are passage 3'! by an annular insulating plate 75, and one of the iron plates "it which is insulated from the arc was ill) sage 81 by an annular insulating plate 11. Beneath these plates are positioned the two insulating plates 19 and 8| shown in Figs. 11 and 12. It will be noted that the opposed inner surfaces of the plates 15, 11, 18, and 8! define the outline of the arc passage proper 31, and since those surfaces are substantially concentric with each other; the arc passage takes the form of a hollow cylinder.

The remaining portion of each of the are extinguishing devices comprises groups of the previously described plates. The pocket defining set which is disposed beneath the lower plates 19 and 8| are those shown in Figs. 13 and 14. Beneath this is positioned a set of plates shown in Figs. 15 and 16, and this is followed by a second set of the plates shown in Figs. l3 and 14, these plates combining to define the second of the pocket defining groups.

A pair of the plates shown in Figs. 11 and 12 are positioned immediately beneath each of these second pocket defining groups, and this set of plates is followed by one of the sets shown in Figs/9 and 10.

The last group of plates in each of the are extinguishing devices is a pocket defining unit exactly similar to the first of these units which was v described above. Beneath this unit there is po- I stacks is the lower coil 88 for producing a radial field within the arc passage, and the plates which insulate that coil from the central bolt. These coil insulating plates are similar to those previously described, and the uppermost consists of one of the sets of the plates shown in Figs. '7 and 8. This is followed by one of the sets of plates shown .in Figs. 5 and 6. The next set is that shown in Figs. 7 and 8, and the final set is that shown in Figs. 5 and 6. A third arcing plate is positioned at the bottom of each of the stacks in order to permit the lower coil 88 to be energized during the arc extinguishing operation.

A cap member ll of magnetic material and an insulating member 82 exactly similar to the upper members 4| and 82 are positioned at the lower end of each of the arc extinguishing devices and serve in conjunction with the upper cap members to retain the outer plates in their proper positionand to give strength and rigidity to the entire structure. The opposed edges of the two members 4| in each arc extinguishing device are spaced some distance apart in order to prevent breakdown therebetween.

All of the plates which define the arc passage proper are provided with suitable openings 88 therein for engaging insulating pins 85, the ends of which project into similarly disposed openings provided in the arcing plates 55. These pins 85 assure a proper aligning of the various elements of the device during its assembly.

The lower coil 88 is connected between the two lower arcing plates 55, and the upper coil is connected as mentioned before between the frame l9 of the stationary contact structure itself and the upper arcing plate 55. Thus, when the arc is established within the arc passage 31, both of the coils 88 are connected in series therewith, that portion of the are which is drawn between the upper arcing plate 55 and the movable contact 28 being extinguished by virtue of the fact .that the upper coil 88 is in parallel therewith,

and thatthe portion of the are which is drawn between the lower pair of arcing plates being similarly extinguished. The coils 88 are connected so as to form poles of opposite polarity, thereby facilitating the production of radial field within the arc passage. The iron plates 41 and 1| imbedded in the walls which define the arc passage and the magnetic cap members 4| serve to equalize and assure a proper distribution of that field.

From the foregoing, it will be seen that we have disclosed an arc extinguishing device which is provided with a tubular arc passage 81 having the substantial )form of a hollow cylinder wherein the are which is drawn therein by the separation of the cooperating contact members may be moved laterally during the arc extinguishing operation. Both ends of this tubular arc passage 81 are substantially closed by an arcing member 55, thus permitting the arc to be moved laterally therein in recurrent paths, during the circuit interrupting operation, and in addition, the opposed surfaces which define portions of the arc passage 81 are provided with cut-out portions for creating fluid retaining pockets adjacent the path of movement of the arc. This assures an adequate supply of arc extinguishing fluid during the circuit interrupting operation.

Upon the occurrence of an overload capable of effecting the actuation of the operating mechanism, the bridging member I8 is moved in a downwardly direction. Almost immediately after this movement is initiated, the shoulder portion 81 of each of the two movable contact members 28 engage the upper cap member ll forming a part of the-arc extinguishing device associated therewith, and is thereby prevented from following the movement of the bridging member. An arc is thereupon established between the cooperating upstanding end 85 of the bridging member and the contact member 28.

Due to the close proximity of the upper arcing member 55, the arc drawn between the bridging member 85 and the movable contact member 28 will almost immediately contact that member, thereby causing a section of thearc to be in parallel with the upper coil 88. This short section of the arc will thereby be extinguished, since the voltage drop through the coil is less than that necessary to maintain an arc in parallel therewith, and the entire current flowing in the circuit controlled by the breaker will flow through the coil 88.

Upon further downward movement of the bridging member l5 an arc is drawn between the upper arcing member 55 and the first of the two lower arcing members 55. This are is free to move, under the influence of the radial field set up by the coils 88, laterally within the arc passage 81 and is so moved by that field. As the circuit opening operation progresses, the upstanding portions 85 and bridging member l5 are moved entirely without the arc extinguishing devices l8, and that portion of each of the two arcs which exists between the two lower arcing members 55 is extinguished, thereby causing each of the lower radial field coils 88 to be connected in the circuit controlled by the breaker.

The combined result of the above action is to cause the formation of a very strong, are moving, magnetic field (indicated by the arrows in Figs. 3 and 4) within the arc passage. This field efl'ects a very rapid movement of the are within the arc passage, the are moving substantially around the central axis of the arc extinguisher. As a result of this high velocity movement of the arc and its attended gas envelope, extreme local turbulence is produced in proximity to the arc stream. The volatilized are products, vapor and quantities of the arc extinguishing liquid itself are intermixed in such manner that restriking of the are once at a zero point in the current wave has been reached is practically precluded.

The movement of the arc just described also serves to impart considerable kinetic energy to the fluid which is moved in the reentrant arc passage 31. This kinetic energy causes the iluid motion to continue after the occurrence of a zero point in the current wave and results in the moving of a quantity of relatively cool homogeneous fluid between the contact members 35 and 29, and between various portions of the arcing members 55, including the area which was last occupied by the arc.

By moving cooled un-ionized liquid over the heated portions of the arcing members, a particularly beneficial effect is produced. As is well known in the art, if the terminal point of an electric arc is positioned on a metal surface, and is not moved thereon at a very high speed, that surface becomes heated to a very high temperature and may emit a considerable number of electrons, which emission greatly facilitated the restriking .of an arc after the occurrence of a zero point in the current wave. If, however, these heated, electron emitting surfaces are covered by a cooled insulating medium, it becomes much more difhcult for the arc to restrike with the restoration of the voltage, and this is the eifect which is produced with our invention. By virtue of the movement of the arc stream, and the liquid entrapped within the arc passage at, and subsequent, to the occurrence of current zero, the arc is forced to restrike, if it restrikes at all, between cooled metallic surfaces which oflfer the maximum possible impedance to that restriking. So marked is this efiect that we have found that our invention practically precludes the restriking of an are after the occurrence of one zero point in the cur rent wave.

The structure shown in Figs. 19 through 21 operates on essentially the same principles as the previously described embodiment of our invention. That is, the device includes means for defining a substantially tubular arc passage, which is lined with insulated material, means for drawing an are within that passage, and magnetic itBI for engaging the lower end of the conductor 25 disposed within the cooperating insulating bushings I, and a circular plate member lot affixed to this bracket member lili through the agency of a support I 05, the bracket, support, and plate members being cast integral with one another. A cap shaped member ll", of magnetic material, is affixed to the lower surface of plate member I03 by means such as the bolts Hi9, and is threaded on its inner surfaces for engaging a tubular insulating member III which defines the outer walls and one of the two opposed surfaces of the tubular are passage proper 5 l3. 'A coil member I I5, one end of which is electrically con= nected to'the plate portion I03 of the stationary contact frame, and the other end of which is connected to an annularly shaped contact member i H, is positioned immediately beneath the coil H5. A hollow contact member H9, supported upon the bridging means I5 is provided for cooperating with the fixed contact I.

A plurality of alternately disposed plates Hi and H23 of insulating material are supported upon .a bolt l25 which is imbedded in insulating material and positioned within the central portion of the arc passage M3. These plates define the inner surfaces of the arcpassage, and by virtue of their diifering diameters form the substantial equivalent of oil pockets.

The support bolt M25 is preferably of magnetic material in order to aid in equalizing the radial field which is produced within the arc passage by the coil iitl.

A developed view of the contact structure of the movable contact H9 is shown in Fig. 21, and it will be seen that this member includes a flattened contact portion l2? adapted to engage the cooperating stationary contact III positioned at the upper end of the arc passage I I3 and a helical portion Mil along which the arc may be moved during the arc extinguishing operation.

The helical portion [I29 is so arranged with respect to the polarity of the coil H5 which produces. the radial magnetic field within the arc passage that the arc is caused to move thereon during its lateral movement in the arc passage itself. Tins movement, as mentioned above, effects a progressive lengthening of the arc, independently of that lengthening which is pro-= duced by the normal downward movement of the bridging member.

The operation of this embodiment of our in-= vention is substantially similar to the operation of the previously described device. Upon the occurrence of a predetermined overload condition, the bridging member I5 is caused to move toward the open circuit position, thereby establishing an are between the contact portion 5217 or the movable, tubular contact member H9 and the plate contact lfl'i supported'at the upper end of the arc passage. The coil I I5 is normally connected in series with the path of current flow through the breaker, and by virtue of the resulting radial field produced within. the arc passage, the arc is caused to move, immediately following its establishment, along the helical surface U29 or" the movable contact member. This movement effects a progressive lengthening of the arc, which lengthening is aided by the downward movement of the contact member itself. The outer surface 01' the larger insulating plates H3 and the inner surface of; the tubular insulating member iii define the surfaces of the arc passage ilt wherein this movement is caused to take place. The smaller plates 12! provide means for assuring that adequate volume of insulating fluid shall be available during the arc extinguishing operation, and as a result a very rapid extinction of the arc is effected.

This modified form of arc extinguisher allows the are to be moved therein in recurrent paths, should some difliculty be experienced in the arc extinguishing operation due to unusual circuit conditions. Further, as the movable contact member 1H9 nears the open circuit position, it opens the lower end of the arc passage M3 to the main body of liquid, thereby allowing the volatilized are products to expulsively flow through the arc stream. This action, in combination with the rotary motion of the are produced by the radial fleld, assures a positive extinction of any arc to which the device may be subjected.

From the foregoing, it will be seen that we have disclosed the features of a new and improved form of circuit interrupting device which operates in accordance with the principles heretofore not generally used in the circuit interrupting art. Those principles include the establishing of an are within a tubular arc passage, having arcing members positioned at either end thereof, and then moving the arc laterally in that passage so as to eflect an intimate comingling of the arc with the un-ionized fluid disposed within the arc passage in order to eflect its extinguishment. Further, by embodying these principles into a fluid type breaker utilizing a continuous arc passage, it is possible to cause the arc stream to move the entrapped fluid in a manner similar to a piston, thereby assuring that a fresh supply of arc extinguishing fluid will be swept between the live parts to insure against the restriking of the arc, and that the heated portions of the arcing members which might be raised to a temperature capable of effecting independent emission of electrons will be covered with insulating medium when the arc is extinguished at a zero point in the current wave. 'Ihis arrangement produces great turbulence within the arc stream during the circuit interrupting operation and makes it necessary for the arc to restrike, if it restrikes at all, between cold surfaces.

We have also shown how this arrangement of a tubular arc passage and means for laterally moving the arc therein during the circuit interrupting operation may be employed for effecting a progressive lengthening of the arc, independment of an arc maybe caused to effect the introduction of fresh dielectric into the space between the are drawing members during the progress of the circuit interrupting operation. When this feature is combined with the above described method for eflecting a progressive lengthening of the arc during its lateral movement, a particularly desirable result is brought about, in that the arc is prevented from restriking across the space between the relatively close arc drawing members and is forced to restrike, if it restrikes at all, between the diverging arcing horns. In the above described embodiments, we have disclosed how our invention could be applied to circuit interrupters of the liquid type. The principles of laterally .moving an arc in a reentrant arc passage may well be applied to breakers which are not liquid immersed, and it is our intention that the language of the accompanying claims shall cover such devices. In fact, in the structures shown, the liquid itself is not depended upon entirely for producing the are extinguishing gas, the several insulating plates being formed of fiber or other material which is itself capable of evolving arc extinguishing gas when placed in proximity to an electric arc.

While in acordance with the patent statutes we have disclosed the foregoing details of certain operative embodiments of our invention, it is to be understood that many of these details are merely illustrative. It is our desire, therefore, that the language of the accompanying claims shall be accorded the broadest reasonable construction, and that our invention shall be limited only by what is expressly stated therein and by the prior art.

We claim the following as our invention:

1. In a circuit interrupter, means of insulating material having walls for defining a tubular shaped narrow endless slot therebetween, an arc terminal member disposed in one end of said narrow slot having an endless arc path thereon, a tubular contact member movable longitudinally in said slot for establishing'an arc therein. between said arc terminal member and said contact member, said contact member having an endless arc path thereon inclined with respect to the arc path on said arc terminal member, and means for producing a magnetic fleld radially across said slot for rotating said are in at least one, long section between said are terminal member and said contact member in a direction to progressively lengthen the are independently of. the movement of said contact member, and means along said slot which gives off a gas when acted upon by said are to aid in extinguishing the arc.

2. In an arc extinguisher, means of insulating material having walls for defini a tubular shaped narrow recurrent slot therebetween, said slot having suilicient length to permit an arc to play therein in one long section, a pair of spaced arc terminal members within said slot having generally annular are paths thereon between which an arc may play, at least one of said are terminal members having a, portion of its arc path inclined with respect to the arc path on the other arc terminal member, a coil positioned coaxialLv with respect to said slot for producing a magnetic fleld radially across said slot to'rotate the arc laterally in one section therein, members of magnetic material embedded in said walls for producing a uniform distribution of said magnetic fleld, and a material along said slot which produces a gas when acted upon by an arc to aid in extinguishing the are. I

3. In a circuit interrupter, means of insulating material for defining a 'tubular shaped narrow endless slot therebetween, a pair of opposed annularly shaped arc terminal members disposed within said passage, each of said are terminal members having an annular arc path'thereon, at least one of said are terminal members having a portion of its arc path divergent with respect to the other are path, means for establishing an are be tween said are terminal members, means for rotating said are laterally in at least one section between said are terminal members, substantially the whole of said slot being so narrow as to prevent substantially any movement of the arc in a direction lateral to the path of rotation, and means along said passage which gives 01! a gas when acted upon by said arc to aid in extinguishing the arc.

4. In an arc extinguisher, means defining a substantially annular shaped narrow slot, said slot being continuous and having considerable length in proportion to its width and in which an arc of considerable length is adapted to play in at least one section, a pair of opposed arc terminal members within said slot having annular arc paths thereon, at least one of said are terminal members having a portion of its arc path divergent with respect to the arc path on the other are terminal member, means for moving the arc laterally around said slot with its ends in engagement with said are paths, and a liquid in said slot which gives off a gas when acted upon by an arc to aid in extinguishing the are.

5; In an arc extinguisher, means of insulating material having walls for defining an annular shaped continuous narrow slot therebetween,

, said narrow slot having considerable length in proportion to its width and in which an arc of considerable length may play in at least one section, a pair of opposed arc terminal members within said slot having annular arc paths thereon, at least one of said'arc terminal members having a portion of its arc path divergent with respect to the arc path on the other are terminal member, means for magnetically moving the arc laterally along said walls between said are terminal members, said slot having a plurality of recesses along one or more of its walls, and a material along said walls which gives off a gas when acted upon by an arc to aid in extinguishing the arc.

6. An arc extinguisher comprising means of insulating material having a pair of cylindrical opposed walls defining a continuous annular slot, said slot being of considerable length in proportion to its width, an arc terminal member of generally annular shape disposed in each end of said slot adapted to permit an arc of considerable length to play between said terminals in at least one section, at least one of said are terminal members having a portion thereof inclined with respect to the other are terminal member, at least one coil positioned outside of said slot adjacent one end thereof for providing a magnetic field radially across said slot for moving the arc laterally in one section around said slot with the ends of the arc in contact with said are terminal members, a pole niece of magnetic material par surrounding said coil and adjacent one end o1" id slot for distributing the magnetic field thereacross, said slot being sufliciently restricted in width to prevent substantially any movement thereof in a direction lateral to the path of rotatlon, and a liquid in said slot which gives off a gas when acted upon by an arc to aid in extin- 

